Kinematics of the head and associated vertebral artery length changes during high-velocity, low-amplitude cervical spine manipulation.

BACKGROUND: Cervical spine manipulation (CSM) is a frequently used treatment for neck pain. Despite its demonstrated efficacy, concerns regarding the potential of stretch damage to vertebral arteries (VA) during CSM remain. The purpose of this study was to quantify the angular displacements of the head relative to the sternum and the associated VA length changes during the thrust phase of CSM. METHODS: Rotation and lateral flexion CSM procedures were delivered bilaterally from C1 to C7 to three male cadaveric donors (Jan 2016-Dec 2019). For each CSM the force-time profile was recorded using a thin, flexible pressure pad (100-200 Hz), to determine the timing of the thrust. Three dimensional displacements of the head relative to the sternum were recorded using an eight-camera motion analysis system (120-240 Hz) and angular displacements of the head relative to the sternum were computed in Matlab. Positive kinematic values indicate flexion, left lateral flexion, and left rotation. Ipsilateral refers to the same side as the clinician's contact and contralateral, the opposite. Length changes of the VA were recorded using eight piezoelectric ultrasound crystals (260-557 Hz), inserted along the entire vessel. VA length changes were calculated as D = (L1 - L0)/L0, where L0 = length of the whole VA (sum of segmental lengths) or the V3 segment at CSM thrust onset; L1 = whole VA or V3 length at peak force during the CSM thrust. RESULTS: Irrespective of the type of CSM, the side or level of CSM application, angular displacements of the head and associated VA length changes during the thrust phase of CSM were small. VA length changes during the thrust phase were largest with ipsilateral rotation CSM (producing contralateral head rotation): [mean ± SD (range)] whole artery [1.3 ± 1.0 (- 0.4 to 3.3%)]; and V3 segment [2.6 ± 3.6 (- 0.4 to 11.6%)]. CONCLUSIONS: Mean head angular displacements and VA length changes were small during CSM thrusts. Of the four different CSM measured, mean VA length changes were largest during rotation procedures. This suggests that if clinicians wish to limit VA length changes during the thrust phase of CSM, consideration should be given to the type of CSM used.

Effects of spinal manipulative therapy on inflammatory mediators in patients with non-specific low back pain: a non-randomized controlled clinical trial.

BACKGROUND: The inflammatory profiles of patients with acute and chronic nonspecific low back pain (LBP) patients are distinct. Spinal manipulative therapy (SMT) has been shown to modulate the production of nociceptive chemokines differently in these patient cohorts. The present study further investigates the effect(s) of SMT on other inflammatory mediators in the same LBP patient cohorts. METHODS: Acute (n = 22) and chronic (n = 25) LBP patients with minimum pain scores of 3 on a 10-point numeric scale, and asymptomatic controls (n = 24) were recruited according to stringent exclusion criteria. Blood samples were obtained at baseline and after 2 weeks during which patients received 6 SMTs in the lumbar or lumbosacral region. The in vitro production of tumor necrosis factor (TNFα), interleukin-1 ß (IL-1ß), IL-6, IL-2, interferon É£ (IFNÉ£), IL-1 receptor antagonist (IL-1RA), TNF soluble receptor type 2 (sTNFR2) and IL-10 was determined by specific immunoassays. Parametric as well as non-parametric statistics (PAST 3.18 beta software) was used to determine significance of differences between and within study groups prior and post-SMT. Effect size (ES) estimates were obtained using Cohen's d. RESULTS: Compared with asymptomatic controls, SMT-related change scores were significant (P = 0.03-0.01) in reducing the production levels of TNFα in both patient cohorts and those of IL-6, IFNÉ£ and sTNFR2 (P = 0.001-0.02) in patients with chronic LBP. Above-moderate to large ES (d > 0.6-1.4) was observed for these mediators. Compared with respective baselines, a significant post-SMT reduction (P = 0.01) of IL-6 production was detected only in patients with chronic LBP while a significant increase of IL-2 production (P = 0.001 vs. control, and P = 0.004 vs. chronic LBP group) and a large ES (d = 0.87) were observed in patients with acute LBP. Pain and disability scores declined significantly (P < 0.001) in all LBP patients, and were positively correlated (P = 0.03) with IFNÉ£ and IL-2 levels in the acute LBP cohort. CONCLUSION: The short course of SMT treatments of non-specific LBP patients resulted in significant albeit limited and diverse alterations in the production of several of the mediators investigated in this study. This exploratory study highlights the potential of SMT to modulate the production of inflammatory components in acute and chronic non-specific LBP patients and suggests a need for further, randomized controlled clinical trials in this area. TRIAL REGISTRATION: This study was prospectively registered April 2012 with Clinical Trials.gov ( #NCT01766141 ). https://register.clinicaltrials.gov/prs/app/action/SelectProtocol?sid=S0003ZIL&selectaction=Edit&uid=U0001V74&ts=2&cx=-axvqtg.

Force transmission between thoracic and cervical segments of the spine during prone-lying high-velocity low-amplitude spinal manipulation: A proof of principle for the concept of regional interdependence.

BACKGROUND: Regional interdependence is conceptually based on observations that applying manual therapy to a remote anatomical region has an effect in the area of the patient's primary complaint. The current model for regional interdependence depends on force transmissibility within the body. This investigation sought to determine transmissibility between forces applied to the thoracic spine during prone-lying high-velocity low-amplitude spinal manipulative therapy and the cervical spine. METHODS: A chiropractic treatment table was modified to allow (or disallow) translation of the headrest in the caudal-cephalad direction when unlocked (or locked). Prone-lying high-velocity low-amplitude spinal manipulative therapy was applied to the thoracic region of 9 healthy participants with the headrest in both configurations. Head and thorax kinematics and kinetics were measured at interfaces between participant and the external environment, which included the clinician's hands. Compressive forces at the cervicothoracic junction and angular kinematics of the cervical spine were derived. Ratios between the clinician-applied forces (input) and the cervical compressive force (output) were also determined. FINDINGS: The cervical spine extended during all high-velocity low-amplitude spinal manipulative therapy trials. Force input-to-output ratios exceeded 1 for high-velocity low-amplitude spinal manipulative therapy trials performed with the headrest in the locked configuration, which was greater than ratios for the unlocked configuration. INTERPRETATION: Forces imparted to thoracic spine during high-velocity low-amplitude spinal manipulative therapy were transmitted to the cervical spine, which provided a precursor for the regional interdependence model for manual therapy. Friction between the participant's face and the treatment table's head rest likely amplified cervical compressive forces.

Nonspecific Low Back Pain: Inflammatory Profiles of Patients With Acute and Chronic Pain.

BACKGROUND: The pathogenesis of low back pain (LBP) remains unclear. However, recent studies suggest that the inflammatory response may be inherent in spinal pain. The purpose of this study was to discern inflammatory profiles in patients with nonspecific acute and chronic LBP in relation to those in asymptomatic individuals. MATERIALS AND METHODS: Peripheral blood samples were obtained from asymptomatic controls and patients with nonspecific acute and chronic LBP reporting a minimum pain score of 3 on a 10-point Visual Analogue Scale (VAS). The levels of in vitro production of proinflammatory (tumor necrosis factor α [TNFα], interleukin [IL] 1ß, IL-6, IL-2, interferon γ) and anti-inflammatory (IL-1 receptor antagonist, soluble receptors of TNF2, and IL-10) mediators were determined by specific immunoassays. RESULTS: The mean VAS scores were comparable between the acute and chronic LBP patient groups. Compared with asymptomatic group, the production of TNFα, IL-1ß, IL-6 and their ratios to IL-10 levels were significantly elevated in both patient groups (P=0.0001 to 0.003). In acute LBP group, the ratio of IL-2:IL-10 was also significantly increased (P=0.02). In contrast, the production of interferon γ was significantly reduced compared with the other study groups (P=0.005 to 0.01), nevertheless, it was positively correlated (P=0.006) with pain scores. In chronic LBP patients, the production of TNFα, IL-1 receptor antagonist, and soluble receptors of TNF2 was significantly increased (P=0.001 to 0.03) in comparison with the control and acute LBP groups, and TNFα and IL-1ß levels were positively correlated (P<0.001) with VAS scores. CONCLUSIONS: The inflammatory profiles of patients with acute and chronic LBP are distinct. Nonetheless, in both patient groups, an imbalance between proinflammatory and anti-inflammatory mediator levels favors the production of proinflammatory components.

Effect of cervical manipulation on vertebral artery and cerebral haemodynamics in patients with chronic neck pain: a crossover randomised controlled trial.

OBJECTIVE: It is hypothesised that cervical manipulation may increase the risk of cerebrovascular accidents. We aimed to determine whether cervical spine manipulation is associated with changes in vertebral artery and cerebrovascular haemodynamics measured with MRI compared with neutral neck position and maximum neck rotation in patients with chronic neck pain. SETTING: The Imaging Research Centre at St. Joseph's Hospital in Hamilton, Ontario, Canada. PARTICIPANTS: Twenty patients were included. The mean age was 32 years (SD ±12.5), mean neck pain duration was 5.3 years (SD ±5.7) and mean neck disability index score was 13/50 (SD ±6.4). INTERVENTIONS: Following baseline measurement of cerebrovascular haemodynamics, we randomised participants to: (1) maximal neck rotation followed by cervical manipulation or (2) cervical manipulation followed by maximal neck rotation. The primary outcome, vertebral arteries and cerebral haemodynamics, was measured after each intervention and was obtained by measuring three-dimensional T1-weighted high-resolution anatomical images, arterial spin labelling and phase-contrast flow encoded MRI. Our secondary outcome was functional connectivity within the default mode network measured with resting state functional MRI. RESULTS: Compared with neutral neck position, we found a significant change in contralateral blood flow following maximal neck rotation. There was also a significant change in contralateral vertebral artery blood velocity following maximal neck rotation and cervical manipulation. We found no significant changes within the cerebral haemodynamics following cervical manipulation or maximal neck rotation. However, we observed significant increases in functional connectivity in the posterior cerebrum and cerebellum (resting state MRI) after manipulation and maximum rotation. CONCLUSION: Our results are in accordance with previous work, which has shown a decrease in blood flow and velocity in the contralateral vertebral artery with head rotation. This may explain why we also observed a decrease in blood velocity with manipulation because it involves neck rotation. Our work is the first to show that cervical manipulation does not result in brain perfusion changes compared with a neutral neck position or maximal neck rotation. The changes observed were found to not be clinically meaningful and suggests that cervical manipulation may not increase the risk of cerebrovascular events through a haemodynamic mechanism. TRIAL REGISTRATION NUMBER: NCT02667821.

Elevated Production of Nociceptive CC Chemokines and sE-Selectin in Patients With Low Back Pain and the Effects of Spinal Manipulation: A Nonrandomized Clinical Trial.

BACKGROUND: The involvement of inflammatory components in the pathophysiology of low back pain (LBP) is poorly understood. It has been suggested that spinal manipulative therapy (SMT) may exert anti-inflammatory effects. PURPOSE: The purpose of this study was to determine the involvement of inflammation-associated chemokines (CC series) in the pathogenesis of nonspecific LBP and to evaluate the effect of SMT on that process. METHODS: Patients presenting with nonradicular, nonspecific LBP (minimum pain score 3 on 10-point visual analog scale) were recruited according to stringent inclusion criteria. They were evaluated for appropriateness to treat using a high velocity low amplitude manipulative thrust in the lumbar-lumbosacral region. Blood samples were obtained at baseline and following the administration of a series of 6 high velocity low amplitude manipulative thrusts on alternate days over the period of 2 weeks. The in vitro levels of CC chemokine ligands (CCL2, CCL3, and CCL4) production and plasma levels of an inflammatory biomarker, soluble E-selectin (sE-selectin), were determined at baseline and at the termination of treatments 2 weeks later. RESULTS: Compared with asymptomatic controls baseline production of all chemokines was significantly elevated in acute (P=0.004 to <0.0001), and that of CCL2 and CCL4 in chronic LBP patients (P<0.0001). Furthermore, CCL4 production was significantly higher (P<0.0001) in the acute versus chronic LBP group. sE-selectin levels were significantly higher (P=0.003) in chronic but not in acute LBP patients. Following SMT, patient-reported outcomes showed significant (P<0.0001) improvements in visual analog scale and Oswestry Disability Index scores. This was accompanied by a significant decline in CCL3 production (P<0.0001) in both groups of patients. Change scores for CCL4 production differed significantly (P<0.0001) only for the acute LBP cohort, and no effect on the production of CCL2 or plasma sE-selectin levels was noted in either group. CONCLUSIONS: The production of chemotactic cytokines is significantly and protractedly elevated in LBP patients. Changes in chemokine production levels, which might be related to SMT, differ in the acute and chronic LBP patient cohorts.

Ultrasound Assessment of Abdominal Muscle Thickness in Women With and Without Low Back Pain During Pregnancy.

OBJECTIVE: The aim of this preliminary study was to determine the differences in abdominal musculature thickness, within 1 month of delivery, in women who experienced back pain during pregnancy compared with those who did not. METHODS: B-mode ultrasound imaging was used to measure abdominal muscle thickness on 76 postpartum participants who participated in a larger study; 47 women experienced back pain during pregnancy, and 29 did not. Participant data were stratified by group, and primary comparisons were based on these grouping across the abdominal muscles, including rectus abdominis (upper and lower fibers), external oblique, internal oblique, and transversus abdominis. Means and standard deviations were also used to set parameters for future studies. RESULTS: In the present study, there was no difference in any abdominal muscle thickness between groups. Women with low back pain were significantly shorter (165.19 ± 6.64 cm) than women who did not have from back pain during pregnancy (169.38 ± 7.58 cm). All other demographics, such as age, weight, and date tested postpartum, were not significantly different between groups. CONCLUSION: The results of this study showed no variation in abdominal muscle thickness in women who had back pain during pregnancy and those who did not.

Manipulation Peak Forces Across Spinal Regions for Children Using Mannequin Simulators.

OBJECTIVE: The purpose of this work was to create an exploratory database of manipulation treatment force variability as a function of the intent of an experienced clinician sub-specializing in the care of children to match treatment to childhood category. Data of this type are necessary for realistic planning of dose-response and safety studies on therapeutic benefit. METHODS: The project evaluated the transmitted peak forces of procedures applied to mannequins of different stature for younger and older children. Common procedures for the cervical, thoracic, and lumbar spine and sacroiliac joint were administered to estimate variability by a single experienced practitioner and educator in pediatric manipulation attempting to modulate for childhood category. Results described for peak components in the cardinal axes and for peak total forces were cataloged and compared with consensus estimates of force from the literature. RESULTS: Mean force values for both components and total force peaks monotonically increased with childhood category analogous to consensus expectations. However, a mismatch was observed between peak values measured and consensus predictions that ranged by a factor of 2 to 3.5, particularly in the upper categories. Quantitative data permit a first estimate of effect size for future clinical studies. CONCLUSIONS: The findings of this study indicate that recalibration of spinal manipulation performance of experienced clinicians toward arbitrary target values similar to consensus estimates is feasible. What is unclear from the literature or these results is the identity of legitimate target values that are both safe and clinically effective based on childhood categories in actual practice.

Procedure Selection and Patient Positioning Influence Spine Kinematics During High-Velocity, Low-Amplitude Spinal Manipulation Applied to the Low Back.

OBJECTIVES: This investigation compared indirect 3-dimensional angular kinematics (position, velocity, and acceleration) of the lumbar spine for 2 different high-velocity, low-amplitude (HVLA) spinal manipulation procedures (lumbar spinous pull or push), and altered initial patient lower limb posture. METHODS: Twenty-four participants underwent 6 HVLA procedures directed toward the presumed L4 vertebra, reflecting each combination of 2 variants of a spinal manipulation application technique (spinous pull and push) and 3 initial hip flexion angles (0°, 45°, and 90°) applied using a right lateral recumbent patient position. All contact forces and moments between the patient and the external environment, as well as 3-dimensional kinematics of the patient's pelvis and thorax, were recorded. Lumbar spine angular positions, velocities, and accelerations were analyzed within the preload and impulse stages of each HVLA trial. RESULTS: Lumbar spine left axial rotation was greater for the pull HVLA. The pull HVLA also generated a greater maximum (leftward) and lower minimum (rightward) axial rotation velocity and deceleration and greater leftward and rightward lateral bend velocities, acceleration, and deceleration components. Not flexing the hip produced the greatest amount of extension, as well as the lowest axial rotation and maximum axial rotation acceleration during the impulse. CONCLUSIONS: This investigation provides basic kinematic information for clinicians to understand the similarities and differences between 2 HVLA side-lying manipulations in the lumbar spine. Use of these findings and novel technology can drive future research initiatives that can both affect clinical decision making and influence teaching environments surrounding spinal manipulative therapy skill acquisition.

Patient-Induced Reaction Forces and Moments Are Influenced by Variations in Spinal Manipulative Technique.

STUDY DESIGN: An in vivo biomechanical study. OBJECTIVE: The aim of the present study was to quantify and compare the reaction loads for two spinal manipulation therapy (SMT) procedures commonly used for low back pain using a biomechanical computer model. SUMMARY OF BACKGROUND DATA: Contemporary computer-driven rigid linked-segment models (LSMs) have made it feasible to analyze low back kinetics and kinematics during various activities including SMT procedures. Currently, a comprehensive biomechanical model analyzing actual differences in loading effects between different SMT procedures is lacking. METHODS: Twenty-four healthy/asymptomatic participants received a total of six SMT applications, representing all combinations of two similar SMT procedures within three patient hip flexion angles. All contact forces, patient torso kinematics, and inertial properties were entered into a dynamic three-dimensional LSM to calculate lumbar reaction forces and moments. Peak net applied force along with the maximums, minimums, and ranges for each component of the three-dimensional reaction force and moment vectors during each SMT procedure was analyzed. RESULTS: One specific SMT technique (lumbar spinous pull) produced greater maximum anterior-posterior reaction force and both lateral bending and axial twisting reaction moments compared to the other technique (lumbar push procedure [all P ≤ 0.034]). SMT trials without hip flexion had lower maximum medial-lateral reaction force and range compared to those with 45 and 90 degrees of hip flexion (all P ≤ 0.041). There were no interactions between procedure and hip angle for any of the dependent measurements. CONCLUSION: The technique used to apply SMT and the participant's initial hip orientation induced significantly different actions on the low back. These findings and future research can improve patient outcomes and safety by informing clinicians on how to best use SMT given specific types of low back pain. LEVEL OF EVIDENCE: 2.

Core and Complementary Chiropractic: Lowering Barriers to Patient Utilization of Services.

OBJECTIVE: The use of chiropractic services has stalled while interest in accessing manipulation services is rising. The purpose of this paper is to consider this dilemma in the context of the dynamics of professional socialization, surveys of public attitudes, and a potential strategic action. DISCUSSION: This is a reflection work grounded in the literature on professional socialization and the attitudes held regarding chiropractic in modern society, to include its members, and in original data on training programs. Data were interpreted on the background of the authors' cross-cultural experiences spanning patient care, research, education, and interprofessional collaboration. Recommendation on a strategic action to counter barriers in patient referrals was synthesized. Professional socialization is the process by which society enables professional privilege. Illustration of typical and divergent professional socialization models emerged that explain cognitive dissonance toward the profession. Questions of trust are commensurate with the experiences during patient encounters rather than with a common identity for the profession. Diversity among encounters perpetuates the uncertainty that affects referral sources. Commonality as an anchor for consistent professional identity and socialization through the content of core chiropractic, defined by training and practice, offers a means to offset uncertainty. Complementary chiropractic, analogous to complementary medicine, provides an outlet under professional socialization for the interests to explore additional methods of care. CONCLUSION: The practice workplace is an effective lever for altering barriers to the use of services. Clarifying rhetoric through conceptualization of core and complementary practices simplifies the socialization dynamic. Further, it takes advantage of accepted cultural semantics in meaningful analogy while continuing to empower practical diversity in care delivery in response to evolving scientific evidence.

Effects of Axial Torsion on Disc Height Distribution: An In Vivo Study.

OBJECTIVES: Axial rotation of the torso is commonly used during manipulation treatment of low back pain. Little is known about the effect of these positions on disc morphology. Rotation is a three-dimensional event that is inadequately represented with planar images in the clinic. True quantification of the intervertebral gap can be achieved with a disc height distribution. The objective of this study was to analyze disc height distribution patterns during torsion relevant to manipulation in vivo. METHODS: Eighty-one volunteers were computed tomography-scanned both in supine and in right 50° rotation positions. Virtual models of each intervertebral gap representing the disc were created with the inferior endplate of each "disc" set as the reference surface and separated into 5 anatomical zones: 4 peripheral and 1 central, corresponding to the footprint of the annulus fibrosus and nucleus pulposus, respectively. Whole-disc and individual anatomical zone disc height distributions were calculated in both positions and were compared against each other with analysis of variance, with significance set at P < .05. RESULTS: Mean neutral disc height was 7.32 mm (1.59 mm). With 50° rotation, a small but significant increase to 7.44 mm (1.52 mm) (P < .0002) was observed. The right side showed larger separation in most levels, except at L5/S1. The posterior and right zones increased in height upon axial rotation of the spine (P < .0001), whereas the left, anterior, and central decreased. CONCLUSIONS: This study quantified important tensile/compressive changes disc height during torsion. The implications of these mutually opposing changes on spinal manipulation are still unknown.

Development of a Linked Segment Model to Derive Patient Low Back Reaction Forces and Moments During High-Velocity Low-Amplitude Spinal Manipulation.

OBJECTIVE: The purpose of this paper is to present the experimental setup, the development, and implementation of a new scalable model capable of efficiently handling data required to determine low back kinetics during high-velocity low-amplitude spinal manipulation (HVLA-SM). METHODS: The model was implemented in Visual3D software. All contact forces and moments between the patient and the external environment (2 clinician hand contact forces, 1 contact force between the patient and the treatment table), the patient upper body kinematics, and inertial properties were used as input. Spine kinetics and kinematics were determined from a single HVLA-SM applied to one healthy participant in a right side-lying posture to demonstrate the model's utility. The net applied force was used to separate the spine kinetic and kinematic time-series data from the HVLA-SM into preload as well as early and late impulse phases. RESULTS: Time-series data obtained from the HVLA-SM procedure showed that the participant's spine underwent left axial rotation, combined with extension, and a reduction in left lateral bending during the procedure. All components of the reaction force, as well as the axial twist and flexion/extension reaction moments demonstrated a sinusoidal pattern during the early and late impulse phases. During the early impulse phase, the participant's spine experienced a leftward axial twisting moment of 37.0 Nm followed by a rightward moment of -45.8 Nm. The lateral bend reaction moment exhibited a bimodal pattern during the early and late impulse phases. CONCLUSION: This model was the first attempt to directly measure all contact forces acting on the participant/patient's upper body, and integrate them with spine kinematic data to determine patient low back reaction forces and moments during HVLA-SM in a side-lying posture. Advantages of this model include the brevity of data collection (<1 hour), and adaptability for different patient anthropometries and clinician-patient contacts.

Differential displacement of soft tissue layers from manual therapy loading.

BACKGROUND: Understanding the biomechanics of spinal manipulative therapy requires knowing how loads are transmitted to deeper structures. This investigation monitored displacement at sequential depths in thoracic paraspinal tissues parallel with surface load directions. METHODS: Participants were prone and a typical preload maneuver was applied to thoracic tissues. Ultrasound speckle tracking synchronously monitored displacement and shear deformation of tissue layers in a region of interest adjacent to load application to a depth of 4 cm. Cumulative and shearing displacements along with myoelectric activity were quantitatively estimated adjacent to loading site. FINDINGS: The cephalocaudal cumulative displacement in layers parallel to the surface were, in order of depth, 1.27 (SD=0.03), 1.18 (SD=0.02), and 1.06 (SD=0.01) mm (P<0.000), respectively. The superficial/intermediate shear was 2.1 ± 2.3% whereas the intermediate/deep shear was 4.4% (SE=3.7, P=0.014). Correlation of tissue layers was stronger with application site displacement at the surface (0.87

Effect of Interactive Neurostimulation Therapy on Inflammatory Response in Patients With Chronic and Recurrent Mechanical Neck Pain.

OBJECTIVE: The purpose of this study is to evaluate the effect of treatment with a novel noninvasive interactive neurostimulation device (InterX5000) on the production of inflammatory biomarkers in chronic and recurrent mechanical neck pain (NP) syndrome. METHODS: This study represents pilot biological data from a randomized controlled clinical trial. Twenty-five NP patients and 14 asymptomatic subjects included for baseline comparison only completed the study. The patients received 6 InterX5000 or placebo treatments within 2 weeks, and pretreatment and post-treatment blood samples were collected for in vitro determination of biomarker production. Whole blood cell cultures were activated by lipopolysaccharide or by the combination of lipopolysaccharide and phytohemagglutinin for 24 to 48 hours. The levels of tumor necrosis factor α (TNFα) and its soluble type II receptor (sTNFR II), interleukin (IL) 1, IL-1 receptor antagonist (IL-1RA), IL-6, IL-10, and monocyte chemotactic protein (CCL2/MCP-1) were determined by specific immunoassays. RESULTS: Compared with asymptomatic subjects, baseline production levels of all proinflammatory mediators (TNFα, IL-1ß, IL-6, and CCL2/MCP-1) were significantly augmented or trended higher (P = .000-.008) in patients with NP. Of the anti-inflammatory markers, only IL-1RA was significantly elevated (P = .004). The increase in IL-10 and tumor necrosis factor receptor II levels did not reach statistical significance. Neither InterX5000 nor placebo therapy had any significant effect on the production of the inflammatory mediators over the study period. CONCLUSION: This investigation determined that inflammatory cytokine pathways are activated in NP patients but found no evidence that a short course of InterX5000 treatment normalized the production of inflammatory biomarkers.

Consistency and malleability of manipulation performance in experienced clinicians: a pre-post experimental design.

OBJECTIVE: The purpose of this study was to sample the stability of spinal manipulation performance in peak impulse force development over time and the ability of clinicians to adapt to arbitrary target levels with short-duration training. METHODS: A pre-post experimental design was used. Human analog mannequins provided standardized simulation for performance measures. A convenience sample was recruited consisting of 41 local doctors of chiropractic with 5 years of active clinical practice experience. Thoracic impulse force was measured among clinicians at baseline, after 4 months at pretraining, and again posttraining. Intraclass correlation coefficient values and within-subject variability defined consistency. Malleability was measured by reduction of error (paired t tests) in achieving arbitrary targeted levels of force development normalized to the individual's typical performance. RESULTS: No difference was observed in subgroup vs baseline group characteristics. Good consistency was observed in force-time profiles (0.55 ≤ intraclass correlation coefficient ≤ 0.75) for force parameters over the 4-month interval. With short intervals of focused training, error rates in force delivery were reduced by 23% to 45%, depending on target. Within-subject variability was 1/3 to 1/2 that of between-subject variability. Load increases were directly related to rate of loading. CONCLUSION: The findings of this study show that recalibration of spinal manipulation performance of experienced clinicians toward arbitrary target values in the thoracic spine is feasible. This study found that experienced clinicians are internally consistent in performance of procedures under standardized conditions and that focused training may help clinicians learn to modulate procedure characteristics.

Ultrasound Assessment of Abdominal Muscle Thickness in Postpartum vs Nulliparous Women.

OBJECTIVE: The purpose of this study was to determine the effect size in measurable change of abdominal musculature morphology using ultrasonography in postpartum women within 1 month of a healthy, vaginal delivery. METHODS: One hundred fifty-six participants were recruited for this study. B-mode ultrasound imaging was used to measure abdominal muscle thickness on 80 nulliparous women and 76 mothers who had delivered within the past 4 weeks. Measures were taken for the upper and lower rectus abdominus, external and internal obliques, and transversus abdominus at rest. RESULTS: Statistically significant differences were found in the thickness of the rectus abdominus muscle at both sites; upper (P < .0001) and lower (P < .0001) as well as the internal oblique (P < .0001). All 3 muscles were thinner in postpartum participants (8.29 ± 1.83 mm, 8.89 ± 2.29 mm, and 7.06 ± 1.82 mm, respectively) within the first month of delivery than in controls (10.82 ± 1.93 mm, 11.13 ± 2.38 mm, and 8.36 ± 1.87 mm, respectively). Large effect sizes were found for the influence of pregnancy on the rectus muscle segments (1.35 for the upper rectus abdominus and 1.00 for the lower rectus abdominus) and a medium effect size for the internal oblique (0.71). No significant differences were observed in the remaining 2 muscles. CONCLUSION: This study showed that there are differences in morphology of the abdominal muscles in pregnant women vs nonpregnant controls. The large effect sizes reported may provide the basis for future studies examining relationships between morphology, functional change, and back pain during pregnancy.

Thresholds of skin sensitivity are partially influenced by mechanical properties of the skin on the foot sole.

Across the foot sole, there are vibration and monofilament sensory differences despite an alleged even distribution of cutaneous afferents. Mechanical property differences across foot sole sites have been proposed to account for these differences. Vibration (VPT; 3 Hz, 40 Hz, 250 Hz), and monofilament (MF) perception threshold measurements were compared with skin hardness, epidermal thickness, and stretch response across five foot sole locations in young healthy adults (n = 22). Perceptual thresholds were expected to correlate with all mechanical property measurements to help address sensitivity differences between sites. Following this hypothesis, the MedArch was consistently found to be the thinnest and softest site and demonstrated the greatest sensitivity. Conversely, the Heel was found to be the thickest and hardest site, and was relatively insensitive across perceptual tests. Site differences were not observed for epidermal stretch response measures. Despite an apparent trend of elevated sensory threshold at harder and thicker sites, significant correlations between sensitivity measures and skin mechanical properties were not observed. Skin hardness and epidermal thickness appeared to have a negligible influence on VPT and minor influence on MF within this young healthy population. When normalized (% greater or smaller than subject mean) to the subject mean for each variable, significant positive correlations were observed between MF and skin hardness (R(2) = 0.422, P < 0.0001) and epidermal thickness (R(2) = 0.433, P < 0.0001) providing evidence that skin mechanics can influence MF threshold. In young healthy adults, differences in sensitivity are present across the foot sole, but cannot solely be accounted for by differences in the mechanical properties of the skin.

Quantifying strain in the vertebral artery with simultaneous motion analysis of the head and neck: a preliminary investigation.

BACKGROUND: Spontaneous vertebral artery dissection has significant mortality and morbidity among young adults. Unfortunately, causal mechanisms remain unclear. The purpose of this study was to quantify mechanical strain in the vertebral artery while simultaneously capturing motion analysis data during passive movements of the head and neck relative to the trunk during spinal manipulation and cardinal planes of motion. METHODS: Eight piezoelectric crystals (four per vertebral artery) were sutured into the lumen of the left and right vertebral arteries of 3 cadaveric specimens. Strain was then calculated as changes in length between neighboring crystals from a neutral head/neck reference position using ultrasound pulses. Simultaneously, passive motion of the head and neck on the trunk was captured using eight infrared cameras. The instantaneous strain arising in the vertebral artery was correlated with the relative changes in head position. FINDINGS: Strain in the contralateral vertebral artery during passive flexion-rotation compared to that of extension-rotation is variable ([df=32]: -0.61

The effect of pressure pain sensitivity and patient factors on self-reported pain-disability in patients with chronic neck pain.

The study was conducted to estimate the extent to which pressure pain sensitivity (PPS) and patient factors predict pain-related disability in patients with neck pain (NP), and to determine if PPS differs by gender. Forty-four participants with a moderate level of chronic NP were recruited for this cross sectional study. All participants were asked to complete self-reported assessments of pain, disability and comorbidity and then underwent PPS testing at 4-selected body locations. Pearson`s r w was computed to explore relationships between the PPS measures and the self-reported assessments. Regression models were built to identify predictors of pain and disability. An independent sample t-test was done to identify gender-related differences in PPS, pain-disability and comorbidity. In this study, greater PPS (threshold and tolerance) was significantly correlated to lower pain-disability (r = -.30 to -.53, p≤0.05). Age was not correlated with pain or disability but comorbidity was (r= 0.42-.43, p≤0.01). PPS at the 4-selected body locations was able to explain neck disability (R(2)=25-28%). Comorbidity was the strongest predictor of neck disability (R(2) =30%) and pain (R(2)=25%). Significant mean differences for gender were found in PPS, disability and comorbidity, but not in pain intensity or rating. This study suggests that PPS may play a role in outcome measures of pain and disability but between-subject comparisons should consider gender and comorbidity issues.